Fuel cell power systems have been proposed as a clean, efficient and environmentally responsible power source for electric vehicles and various other applications. One type of fuel cell power system employs use of a proton exchange membrane (PEM) to catalytically facilitate reaction of fuels (such as hydrogen) and oxidants (such as air or oxygen) into electricity. Typically, the fuel cell power system has more than one fuel cell that includes an anode and a cathode with the PEM therebetween. The anode receives the hydrogen gas and the cathode receives the oxygen. The hydrogen gas is ionized in the anode to generate free hydrogen ions and electrons. The hydrogen ions pass through the electrolyte to the cathode. The hydrogen ions react with the oxygen and the electrons in the cathode to generate water as a byproduct. The electrons from the anode cannot pass through the PEM, and are instead directed through a load to perform work before being sent to the cathode. The work acts to operate the vehicle. Many fuel cells are combined in a fuel cell stack to generate the desired power.
The fuel cell power system can include a high pressure vessel or container for storing hydrogen gas for the fuel cell stack. The high pressure vessel can be charged with hydrogen gas at a filling station and the like. The hydrogen gas is transferred from the filling station to the high-pressure vessel on the vehicle to supply the hydrogen gas to the fuel cell stack as needed.
High-pressure vessels generally require shutoff valves for serviceability and to minimize hydrogen gas release to the ambient atmosphere. Typically, the shutoff valves are electrically-operated solenoid valves. Solenoid valves sufficient for use as shutoff valves need a high electrical current to operate, typically up to about 20 watts/piece. The high current increases fuel consumption and controller costs associated with the high-pressure vessels.
There is a continuing need for a pressure vessel system having an architecture that minimizes the use of electrically-operated solenoid valves.